Title of the Invention

PVC dense layer composition, PVC foamed layer composition, PVC glue layer composition and PVC artificial leather

[Technical Field]

The present invention relates to a PVC dense layer composition, a PVC foamed layer composition and a PVC glue layer composition used for preparing artificial leather, and a PVC artificial leather prepared therefrom. The PVC dense layer composition, the PVC foamed layer composition and the PVC glue layer composition all comprise a molecular sieve adsorbent.

[Background art]

Leather is widely used as a surface decorative material in many fields, such as motor vehicles and home decorating. Common leathers include real leather, polar artificial leathers such as polyvinyl chloride (referred to hereinbelow as PVC) artificial leather, and non-polar artificial leathers such as thermoplastic polyolefin elastomer (TPO) artificial leather, etc.

In recent years, as living standards in society have risen overall, people have begun to pursue healthy lifestyles to an ever increasing extent. Besides paying attention to indoor air quality in the home, consumers have been paying more and more attention to air quality in motor vehicles. The PVC artificial leather that is widely used for interior decoration in motor vehicles is made from raw materials which contain volatile organic compounds (hereinafter referred to as VOCs), such as alcohols, acids and phenyl compounds; for this reason, its odour and VOC emissions have attracted particular attention from OEMs and consumers alike. Following the publication and implementation of GB 27630 “Guidelines for air quality in vehicles”, the requirements of OEMs regarding odour and VOC emissions of motor vehicle interior decoration materials became more and more strict. However, existing PVC artificial leathers struggle to meet the higher requirements of OEMs regarding odour levels and VOC emissions.

Thus, it is hoped to propose a novel technical solution to solve the abovementioned technical problem.

[Summary of the invention]

The technical solution to be solved by the present invention is: to provide a PVC dense layer composition, a PVC foamed layer composition and a PVC glue layer composition for preparing artificial leather, and a PVC artificial leather prepared therefrom, wherein the PVC artificial leather has a low odour level and low VOC emissions.

In order to solve the abovementioned technical problem, the present invention can use the following technical solution: a PVC dense layer composition for preparing artificial leather, the PVC dense layer composition comprising a molecular sieve adsorbent, the molecular sieve adsorbent having a pore size of 0.4 - 1 nm, e.g. 0.4 nm, 0.5 nm, 0.6 nm, 0.7 nm, 0.8 nm, 0.9 nm, 1 nm or a pore size in a range between any two of these values, preferably 0.5 - 0.8 nm; and the molecular sieve adsorbent having a silica-alumina ratio greater than 30, preferably greater than 300, more preferably greater than 800, and more preferably 800 - 1000.

In the present invention, the PVC dense layer composition further comprises a PVC resin, a plasticizer, a stabilizer and a colouring powder. Taking the total weight of PVC resin and plasticizer to be 100 parts, the PVC dense layer composition comprises 40 - 60 parts of PVC resin, 40 - 60 parts of plasticizer, 1 - 5 parts of stabilizer, 1 - 5 parts of colouring powder, and 0.5 - 3 parts of molecular sieve adsorbent, e.g. 0.5 part, 0.7 part, 0.9 part, 1.0 part, 1.2 part, 1.4 part, 1.6 part, 1.7 part, 1.8 part, 2.0 parts, 2.2 parts, 2.4 parts, 2.6 parts, 2.8 parts or 3.0 parts of molecular sieve adsorbent or molecular sieve adsorbent in a range between any two of these values. In the present invention, those skilled in the art can select a conventional PVC resin according to actual needs, e.g. the PVC emulsification powder with product name P440 sold by Shanghai Chlor-alkali, Shanghai, China; or the PVC emulsification powder with product name KVH sold by Formosa Plastics, New Jersey, US; or the PVC emulsification powder with product name PSM-31 sold by Shenyang Chemicals, Shenyang, China.

In the present invention, those skilled in the art can select a conventional plasticizer according to actual needs; it is possible to select an phthalate plasticizer, such as a dialkyl phthalate, or a trimellitate plasticizer, such as trialkyl trimellitate, or a combination of two or more plasticizers.

In the present invention, those skilled in the art can select a conventional stabilizer according to actual needs, e.g. organic epoxy stabilizers, calcium-zinc stabilizers and combinations of both of these, e.g. the calcium-zinc stabilizer with product name MC9656EP sold by Baerlocher Plastic Additives (Jiangsu) Co., Ltd.,

Jiangsu, China.

In the present invention, those skilled in the art can choose to add or not to add a colouring powder according to actual needs; if a colouring powder needs to be added, those skilled in the art can select a conventional colouring powder according to actual needs, and this may be an inorganic pigment or an organic pigment, e.g. iron red, titanium dioxide, iron yellow, chrome yellow and cadmium red.

In the present invention, the molecular sieve adsorbent is a zeolite, and the general formula for the chemical composition thereof is: (M)2/nO- Al203 xSi02-pH20, wherein M is a metal ion, n is the metal ion valence, x is the number of moles of S1O2, also called the silica-alumina ratio, and p is the number of moles of water.

Of course, other auxiliary agents may also be added to the PVC dense layer composition as needed, e.g. antioxidants, UV absorbers, etc. In order to solve the abovementioned technical problem, the present invention can also use the following technical solution: a PVC foamed layer composition for preparing artificial leather, the PVC foamed layer composition comprising a molecular sieve adsorbent, the molecular sieve adsorbent having a pore size of 0.4 - 1 nm, e.g. 0.4 nm, 0.5 nm, 0.6 nm, 0.7 nm, 0.8 nm, 0.9 nm, 1 nm or a pore size in a range between any two of these values, preferably 0.5 - 0.8 nm; and the molecular sieve adsorbent having a silica-alumina ratio greater than 30, preferably greater than 300, more preferably greater than 800, and more preferably 800 - 1000.

In the present invention, the PVC foamed layer composition further comprises a PVC resin, a plasticizer, a stabilizer, a foaming agent, a flame retardant and a colouring powder. Taking the total weight of PVC resin and plasticizer to be 100 parts, the PVC foamed layer composition comprises 40 - 60 parts of PVC resin, 40 - 60 parts of plasticizer, 1 - 5 parts of stabilizer, 1 - 3 parts of foaming agent, 3 - 5 parts of flame retardant, 1 - 3 parts of colouring powder, and 0.5 - 3 parts of molecular sieve adsorbent, e.g. 0.5 part, 0.7 part, 0.9 part, 1.0 part, 1.2 part, 1.4 part, 1.6 part, 1.7 part, 1.8 part, 2.0 parts, 2.2 parts, 2.4 parts, 2.6 parts, 2.8 parts or 3.0 parts of molecular sieve adsorbent or molecular sieve adsorbent in a range between any two of these values.

In the present invention, those skilled in the art can select a conventional PVC resin according to actual needs, e.g. the PVC emulsification powder with product name P440 sold by Shanghai Chlor-alkali, Shanghai, China; or the PVC emulsification powder with product name KVH sold by Formosa Plastics, New Jersey, US; or the PVC emulsification powder with product name PSM-31 sold by Shenyang Chemicals, Shenyang, China.

In the present invention, those skilled in the art can select a conventional plasticizer according to actual needs; it is possible to select an phthalate plasticizer, such as a dialkyl phthalate, or a trimellitate plasticizer, such as trialkyl trimellitate, or a combination of two or more plasticizers. In the present invention, those skilled in the art can select a conventional stabilizer according to actual needs, e.g. organic epoxy stabilizers, calcium-zinc stabilizers and combinations of both of these, e.g. the calcium-zinc stabilizer with product name MC9656EP sold by Baerlocher Plastic Additives (Jiangsu) Co., Ltd.,

Jiangsu, China.

In the present invention, those skilled in the art can select a conventional foaming agent according to actual needs; it is possible to select a physical foaming agent, such as the microsphere foaming agent with product name Y-150D Microspheres sold by Wenzhou Jufeng International Trade Co., Ltd, Zhejiang, China, or a chemical foaming agent, such as azodicarbonamide, or a combination of multiple foaming agents.

In the present invention, those skilled in the art can choose to add or not to add a flame retardant according to actual needs; if a flame retardant needs to be added, those skilled in the art can select a conventional flame retardant according to actual needs, such as aluminium hydroxide, magnesium hydroxide, antimony trioxide, halogen flame retardants, phosphorus flame retardants and nitrogen flame retardants.

In the present invention, those skilled in the art can choose to add or not to add a colouring powder according to actual needs; if a colouring powder needs to be added, those skilled in the art can select a conventional colouring powder according to actual needs, and this may be an inorganic pigment or an organic pigment, e.g. iron red, titanium dioxide, iron yellow, chrome yellow and cadmium red.

In the present invention, the molecular sieve adsorbent is a zeolite, and the general formula for the chemical composition thereof is: (M)2/nO- AbCb xSiC phteO, wherein M is a metal ion, n is the metal ion valence, x is the number of moles of S1O2, also called the silica-alumina ratio, and p is the number of moles of water. In order to solve the abovementioned technical problem, the present invention can also use the following technical solution: a PVC glue layer composition for preparing artificial leather, the PVC glue layer composition comprising a molecular sieve adsorbent, the molecular sieve adsorbent having a pore size of 0.4 - 1 nm, e.g. 0.4 nm, 0.5 nm, 0.6 nm, 0.7 nm, 0.8 nm, 0.9 nm, 1 nm or a pore size in a range between any two of these values, preferably 0.5 - 0.8 nm; and the molecular sieve adsorbent having a silica-alumina ratio greater than 30, preferably greater than 300, more preferably greater than 800, and more preferably 800 - 1000.

In the present invention, the PVC glue layer composition further comprises a PVC resin, a plasticizer and a stabilizer. Taking the total weight of PVC resin and plasticizer to be 100 parts, the PVC glue layer composition comprises 40 - 60 parts of PVC resin, 40 - 60 parts of plasticizer, 1 - 5 parts of stabilizer, and 0.5 - 3 parts of molecular sieve adsorbent, e.g. 0.5 part, 0.7 part, 0.9 part, 1.0 part, 1.2 part, 1.4 part, 1.6 part, 1.7 part, 1.8 part, 2.0 parts, 2.2 parts, 2.4 parts, 2.6 parts, 2.8 parts or 3.0 parts of molecular sieve adsorbent or molecular sieve adsorbent in a range between any two of these values.

In the present invention, those skilled in the art can select a conventional PVC resin according to actual needs, e.g. the PVC emulsification powder with product name P440 sold by Shanghai Chlor-alkali, Shanghai, China; or the PVC emulsification powder with product name KVH sold by Formosa Plastics, New Jersey, US; or the PVC emulsification powder with product name PSM-31 sold by Shenyang Chemicals, Shenyang, China.

In the present invention, those skilled in the art can select a conventional plasticizer according to actual needs; it is possible to select a phthalate plasticizer, such as a dialkyl phthalate, or a trimellitate plasticizer, such as trialkyl trimellitate, or a combination of two or more plasticizers.

In the present invention, those skilled in the art can select a conventional stabilizer according to actual needs, e.g. organic epoxy stabilizers, calcium-zinc stabilizers and combinations of both of these, e.g. the calcium-zinc stabilizer with product name MC9656EP sold by Baerlocher Plastic Additives (Jiangsu) Co., Ltd.,

Jiangsu, China.

In the present invention, the molecular sieve adsorbent is a zeolite, and the general formula for the chemical composition thereof is: (M)2/nO- AbCb xSiC phteO, wherein M is a metal ion, n is the metal ion valence, x is the number of moles of S1O2, also called the silica-alumina ratio, and p is the number of moles of water.

In order to solve the abovementioned technical problem, the present invention can also use the following technical solution: a PVC artificial leather, comprising a skin layer prepared from the abovementioned PVC dense layer composition, and/or a foamed layer prepared from the abovementioned PVC foamed layer composition, and/or a glue layer prepared from the abovementioned PVC glue layer composition.

In the present invention, as is well known to those skilled in the art, the slurry viscosity of the PVC dense layer composition during mixing generally needs to be kept within the range of 3000 - 30000 mpa.s, and the slurry viscosity of the PVC glue layer composition during mixing generally needs to be kept within the range of 4000 - 15000 mpa.s. As is well known to those skilled in the art, the slurry viscosities of the PVC dense layer composition and the PVC glue layer composition are controlled mainly by selecting PVC resins of different viscosities and adjusting the ratio of PVC resin to plasticizer.

In the present invention, as is also well known to those skilled in the art, the PVC resin in the PVC dense layer composition, the PVC resin in the PVC foamed layer composition and the PVC resin in the PVC glue layer composition may the same or different; the plasticizer in the PVC dense layer composition, the plasticizer in the PVC foamed layer composition and the plasticizer in the PVC glue layer composition may the same or different; the stabilizer in the PVC dense layer composition, the stabilizer in the PVC foamed layer composition and the stabilizer in the PVC glue layer composition may the same or different; and the colouring powder in the PVC dense layer composition and the colouring powder in the PVC foamed layer composition may the same or different.

In the present invention, the PVC artificial leather further comprises a paint layer at a surface of the skin layer; those skilled in the art can select a conventional paint layer as needed, preferably a water-based polyurethane paint.

In the present invention, the PVC artificial leather further comprises a base fabric layer below the glue layer, wherein a polyester weft-knitted fabric may be selected for the base fabric layer. Of course, nylon may also be selected as the material of the base fabric layer; with regard to style, warp-knitted or nonwoven fabric may also be selected; and weaving may also be selected as the method of interlacing.

Compared with the prior art, the present invention has the following beneficial effects: the applicants unexpectedly found through much experimentation and research that by adding a molecular sieve adsorbent with a specific pore size (0.4 - 1 nm) and a specific silica-alumina ratio (greater than 30) to the PVC dense layer composition, the PVC foamed layer composition and the PVC glue layer composition, it is possible to effectively reduce the odour level and VOC emissions of a PVC artificial leather prepared therefrom, to meet people’s higher requirements regarding odour level and VOC emissions, effectively increase user pleasure and guarantee user health, thus achieving an unexpected technical effect.

[Detailed Description of Embodiments]

The present invention is explained further below through examples and comparative examples.

Example 1 This example relates to the preparation of a PVC artificial leather. The method used in this example to prepare the PVC artificial leather is a conventional method in the art, and those skilled in the art will know clearly how to select specific equipment, process steps and conditions. Therefore, the description of the preparation process below only relates to key steps and conditions of one of the preparation methods.

Step 1 , mixing

In accordance with the skin layer formula given in Table 1-1 and Table 2, the components of the skin layer formula given in Table 1-1 and Table 2 are put into a mixing tank and then stirred mechanically under vacuum until uniform mixing is achieved. A skin layer PVC slurry is thus obtained.

In accordance with the foamed layer formula given in Table 1-1 and Table 2, the components of the foamed layer formula given in Table 1-1 and Table 2 are put into a mixing tank and then stirred mechanically under vacuum until uniform mixing is achieved. A foamed layer PVC slurry is thus obtained.

In accordance with the glue layer formula given in Table 1-1 and Table 2, the components of the glue layer formula given in Table 1-1 and Table 2 are put into a mixing tank and then stirred mechanically under vacuum until uniform mixing is achieved. A glue layer PVC slurry is thus obtained.

Step 2, coating and base fabric attachment

Using an indirect coating method, first of all, the skin layer PVC slurry is applied to release paper, and then fed into a first-stage oven for plasticizing and setting.

Next, the foamed layer PVC slurry is applied to the skin layer that has plasticized and set, and then fed into a second-stage oven for plasticizing and setting. Next, the glue layer PVC slurry is applied by roller to the foamed layer that has plasticized and set, then a polyester weft-knitted fabric is attached, and fed into a third-stage oven for final setting, to obtain a PVC artificial leather coated material. After leaving the oven, the PVC artificial leather coated material and release paper are separated, and each rolled up separately. The rolled-up PVC artificial leather coated material is sent to a printing stage.

Step 3, printing

In the printing stage, the rolled-up PVC artificial leather coated material is unrolled, then a water-based polyurethane paint is printed onto the skin layer of the PVC artificial leather coated material. Once the water-based polyurethane paint has been printed by means of a printer, the material is fed into an oven to dry, then cooled and rolled up to obtain a printed semi-finished product of rolled-up PVC artificial leather. The printed semi-finished product of PVC artificial leather is sent to an embossing stage.

Step 4, embossing

In the embossing stage, the printed semi-finished product of rolled-up PVC artificial leather is unrolled. After softening a surface of the printed semi-finished product of PVC artificial leather by heating, an embossing roller is used to transfer a surface pattern of the embossing roller to the surface of the PVC artificial leather by pressure. After cooling, a PVC artificial leather with a pattern on the surface thereof is obtained.

Examples 2 - 8

Examples 2 - 8 also relate to the preparation of PVC artificial leathers. The preparation process for the PVC artificial leathers, the paint layer raw materials and the choice of base fabric layer are all exactly the same as in Example 1 ; see Table 1-1, Table 1-2 and Table 2 for the differences.

Comparative examples 1 - 3 Comparative examples 1 - 3 also relate to the preparation of PVC artificial leathers. The preparation process for the PVC artificial leathers, the paint layer raw materials and the choice of base fabric layer are all exactly the same as in Example 1 ; see Table 1 -1 , Table 1 -3 and Table 2 for the differences.

Table 1 - 1

Table 1 - 2

Table 1 - 3

Table 2

Testing of odour levels and VOCs of PVC artificial leathers: Testing of the odour levels of the PVC artificial leathers prepared in Examples 1 - 8 and Comparative examples 1 - 3 was carried out in accordance with Volkswagen’s odour testing method PV 3900 C3. See Table 3 for the test results. The odour characteristics of materials are classified as follows, according to standard specifications: level 1 - no odour; level 2 - there is odour, but no disturbing odour; level 3 - there is obvious odour, but no disturbing odour; level 4 - there is disturbing odour; level 5 - there is strong disturbing odour; level 6 - there is unbearable odour.

Testing of the TVOCs of the PVC artificial leathers prepared in Examples 1 - 8 and Comparative examples 1 - 3 was carried out in accordance with Volkswagen’s total volatile organic compounds (TVOC) testing method, the 2000L bag method. See Table 3 for the test results.

Table 3

It can be seen from the Examples, Comparative examples and test results above that the pore size and Al/Si ratio of the molecular sieve adsorbent jointly affect the odour levels and VOC emissions of the PVC artificial leathers. When a molecular sieve adsorbent with a pore size of 0.4 - 1 nm and a silica-alumina ratio greater than 30 is chosen to be added to the PVC dense layer composition, the PVC foamed layer composition and the PVC glue layer composition, the odour level and VOC emissions of the PVC artificial leather prepared are both low. Within the abovementioned ranges, for a fixed silica-alumina ratio of the molecular sieve adsorbent, the adsorption effect of the molecular sieve adsorbent is better if the pore size of the molecular sieve adsorbent is greater; within the abovementioned ranges, for a fixed pore size of the molecular sieve adsorbent, the adsorption effect of the molecular sieve adsorbent is better if the silica-alumina ratio of the molecular sieve adsorbent is greater. However, once the silica-alumina ratio of the molecular sieve adsorbent exceeds 800, changing the silica-alumina ratio does not have a notable effect on the adsorption effect of the molecular sieve adsorbent. The greater the silica-alumina ratio, the more complex the molecular sieve adsorbent processing technology, and the higher the cost.

It can be understood that in the absence of conflict, the abovementioned embodiments of the present invention may be combined with each other to obtain further embodiments. The various specific technical features described in the particular embodiments above may, in the absence of contradiction, be combined in any suitable manner.

The above examples are merely preferred examples, not all examples, of the present invention. It will be understood that those skilled in the art could make many reasonable changes to the technical solution of the present invention without deviating from the substantial spirit and scope of the present invention, and all such reasonable changes are included in the scope of protection of the present invention